Drill.



H. H. BENNETT.

DRILL.

APPLICATION FILBD'HR 1B, 1911. 1,000,067. Patented Aug. 8,1911.

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UNITED STATES PATENT onirica. i

HABBEY'HAAS BENNETT. or nocxrorm, ILLINOIS, AssrGNon or ONE-HALE lroPAUL c.

SEEGMUELLER, or MoLiNE, ILLINOIS." l

DRILL.

Patented A ug. s, i911.

Application led March 16, 1911. I Serial No. 614,775. v

To all whom 'it may concern:

Be it known that I, HARREY HAAs BEN- acitizen of the United States,residing at Rockford, Winnebago county, Illinois, have invented certainnew and useful Improvements, in Drills,'o` which the following is aspecification.

'Ihis invention, pertaining to improvement-s in drills, will be readily'understood `from the following description taken in connection with'theaccompanying drawing in' l ends of ribs 2 being beveled in drill form,

the diameter across ribs 2 being greater than the diameter across drill1,*and the cutting ends of'ribs 2 being some 'distance in retreat of thecutting end of drill 1, ribs 2 being illustrated as having a twistsimilar -to drill .1: 3,-the cutting -edges of drill 1:

- being produced as the work l40 and 4, the cuttin edges of ribs 2.

The edges of rill land of ribs 2 are formed with the clearance usual indrills.

The diameter across ribs 4 is to'be that of the hole to be produced.

In using the drill, drill 1drills its hole ot4 a size less than that tobe ultimately produced and the cuttingedges of ribs 2 follow inenlarging the hole, a. counter bored hole rogresses, and the completehole, when dr' led through a. piece of work, having Jthe `diameter dueto ribs 2. The heavy is done by drill 1, while the lighter and siz- 'thebar being -less than advance work of drillingl reason voi this divisionof duty there results a breaking of the chips which facilitates clearingas the work progresses. The division ofthe duty between what virtuallyconstitutes 'two drills working simultaneously iin-poses a torsionalstrain upon each ing duty is perforinedfby vribs 2, and byindividualdrill much less `than would be' imposed upon a singledrill-producing `the -saine diameter Aof the hole in the saine material,and the integrally vformed multiple drill possesses superior bodilystrength.' Vhilel the idea, may be vcarried further by' increasing thenumber'of drills embodied in the integral structure,each drill havingitsown individual diameter, the structure illustrated will begfoundpreferable, byv 'reason of sim Aicity and ease of manufacture and easeosharpening.

1. A drill comprising, 'a vfl t bar having cutting edges at its end, andr bs projecting from the sides of said barv and having cuttingedges attheir ends, the Acutting edges of thebar being in advance of the cuttingedges of' the ribs, and the diameter across the diameter across theribs, combined substantially as set forth.

2. Adrill comprising, va-iat bar having cutting edges at its end, ribsprojecting from the sides of said bar and having cutting edges at theirends, the `cutting edges of the bar bein in advance of the cutting edgesof the ri s, and the diameter across the bar being less than thediameter-across the ribs, and said vbar and ribs being` provided with, alongitudinal twist, combined substantially as set forth.

HARREY 11ans BENNETT.v .'witneses:

Gii'onenJ. JOHNSON, E. ANDnnsoN. 4

